共查询到20条相似文献,搜索用时 62 毫秒
1.
2.
3.
<正>阿拉伯木聚糖广泛存在于玉米、小麦、菜粕等植物性饲料原料中,而它不被单胃动物消化利用,当木聚糖进入单胃畜禽小肠后,木聚糖部分溶于水,使食糜含水量增加,进而增加小肠内容物的粘度,阻碍营养物质与消化酶的结合及营养物质在小肠粘膜上的吸 相似文献
4.
畜禽肠道健康的调控已成为当今畜牧业中的重点关注问题。阿拉伯木聚糖(AX)和阿拉伯低聚木糖(AXOS)作为新型的益生元,其对双歧杆菌等益生菌的增殖效果优于低聚果糖等益生元。此外,与低聚果糖等益生元相比,AX和AXOS能够进入肠道后段进行发酵,生成非支链的短链脂肪酸,并抑制蛋白质的发酵,减少有毒物质(苯酚、氨等)的生成,从而有效地调节后肠段(结肠和盲肠)的健康。不同结构的AX和AXOS具有不同的益生功能,且AX和AXOS间存在协同增效的益生作用。本文综述了近年来关于AX和AXOS的益生功能的研究进展,为其在畜牧业中的应用提供一定的理论依据和指导。 相似文献
5.
(接上期)3小麦的主要抗营养因子——阿拉伯木聚糖早在1952年,Preece和Macrenzie就证实了谷物饲料中主要含有两类抗营养因子一木聚糖和β一葡聚糖。在小麦中,木聚糖占整粒的6.6%,β—葡聚糖仅占0.1%,它们都是聚黏性的非淀粉多糖。这些存在于小麦籽粒中阻碍营养物质消化、吸收和利用的物质,称之为抗营养因子。3.1阿拉伯木聚糖的结构Annison等(1992)提出了木聚糖的结构。由于它是由阿拉伯糖和木糖两种单糖组成的,故称之为阿拉伯木聚糖或戊聚糖。这种物质是一类由D一木糖聚合成的主干(由1,4一木吡喃糖残基组成)和L一阿拉伯糖分枝(带有1—2,1—… 相似文献
6.
7.
蛋白质饲料木聚糖含量及其体外酶解效果研究 总被引:6,自引:0,他引:6
本文通过体外酶解试验,考察木聚糖酶对豆粕、菜籽粕和棉籽粕的总木聚糖和水溶性木聚糖的降解效果,试图建立木聚糖酶与不同蛋白质饲料种类的定量关系.试验结果表明:①不同蛋白质饲料的总木聚糖和水溶性木聚糖的含量不同,豆粕、菜籽粕和棉籽粕的总木聚糖含量分别为5.62%、6.56%和8.20%;水溶性木聚糖含量分别为0.35%、0.97%和0.84%;②不同来源的3种蛋白质饲料的总木聚糖和水溶性木聚糖含量变异较小.在适宜的水环境中,菜籽粕的水溶性木聚糖含量显著增加,豆粕和棉籽粕的水溶性木聚糖变化不大;③木聚糖酶对3种蛋白质饲料的总木聚糖均有显著降解作用,对水溶性木聚糖有一定的降解作用,其中对菜籽粕的总木聚糖和水溶性木聚糖的降解作用均较大;以总木聚糖酶为标识,结合考虑成本,豆粕、菜籽粕、棉籽粕的适宜添加木聚糖酶水平分别为1 000、1 000和1 500 U/kg. 相似文献
8.
为了比较农业生产型林业中的木聚糖,使用木聚糖RmXyn10A的两种变体,只有源自海洋红嗜热盐菌的全长酶和催化模块,对硬木(桦木)木聚糖和谷物(黑麦)阿拉伯木聚糖进行水解。用含有水解产物的低聚木糖(XOS)作为碳源,培养4种精选的细菌菌种,结果显示了短乳杆菌DSMZ 1264和青春双歧杆菌ATCC 15703出现选择性生长。这两种菌株被证实可利用低聚木糖组分(DP 2-5);而来自黑麦阿拉伯木聚糖水解产物的假定阿拉伯低聚木糖仅能被青春双歧杆菌利用。大肠杆菌不能生长,但能在单糖阿拉伯糖和木糖上生长。研究还表明,小片球菌(Pediococcus parvulus)2.6株既不能利用木糖,也不能利用低聚木糖进行生长。总之,RmXyn10A或其催化模块证实可用于硬木木聚糖和谷物阿拉伯木聚糖的高温水解,产生XOS,因此能在功能性食品中充当益生元。 相似文献
9.
粘性多糖及多糖酶的研究进展 总被引:7,自引:0,他引:7
饲料中粘性多糖主要以阿拉伯木聚糖和β-葡聚糖为主,它们是麦类谷物及糠麸中的主要多糖,会阻碍畜禽的消化吸收,降低饲料利用率,同时给卫生和疾病控制带来困难。因此,如何充分开发和利用我国资源丰富的麦类谷物及糠麸,是科研工作者目前需要解决的实际问题。1阿拉伯木聚糖和β-葡聚糖的结构阿拉伯木聚糖主要由戊糖(阿拉伯糖和木糖)组成,因此又常称为戊聚糖,由β-(1→4)-右旋-吡喃木糖基主链与一个或多个α-左旋阿拉伯呋喃糖基取代而成(Annison等,1992)。β-葡聚糖是一类由右旋-葡萄糖以β-构型连接的同聚物,由糖基分子线性连结或葡聚糖直链、… 相似文献
10.
木聚糖酶在畜禽生产上的应用 总被引:2,自引:0,他引:2
<正>如何合理利用麦类及杂粕类等非常规饲料原料来降低养殖成本,已成为近年国内动物营养与饲料科学领域的一个研究热点。但非常规饲料原料小麦和杂粕中含有的阿拉伯木聚糖等抗营养因子难于被单胃动物消化吸收,使谷物籽实中的营养物质不能被充分 相似文献
11.
12.
魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
13.
14.
本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
15.
REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
16.
17.
18.
Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献
19.
乳酸杆菌作为益生菌广泛用于人和动物.本文综述了乳酸杆菌改善宿主健康的机制.乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道.文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制. 相似文献